Canadian Health Information Management Association Practice Exam

What is the main function of the kidneys in the urinary system?

1. Produce red blood cells.

2. Filter waste from the bloodstream.

3. Regulate body temperature.

4. Control blood pressure.

The correct answer is: Filter waste from the bloodstream.

The primary function of the kidneys in the urinary system is to filter waste from the bloodstream. This involves removing excess fluids, electrolytes, and metabolic waste products, such as urea and creatinine, from the blood. The kidneys play a crucial role in maintaining the body's fluid and electrolyte balance, which is essential for overall health. They achieve this filtering process through a series of nephrons, which are tiny functional units within the kidneys that carry out filtration and reabsorption. Once the blood has been filtered, the kidneys also help to regulate the pH balance of the body by selectively reabsorbing bicarbonate and secreting hydrogen ions as needed. The waste filtered out is then concentrated into urine, which is excreted through the urinary tract. While the kidneys do have secondary functions, such as producing hormones that regulate blood pressure and stimulating red blood cell production through the release of erythropoietin, their main role remains the filtration and excretion of waste products. This highlights the kidneys' essential role in maintaining homeostasis within the body.